src/core/meshcop/timestamp.hpp

/*
 *  Copyright (c) 2016, The OpenThread Authors.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 *  POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file
 *   This file includes definitions for manipulating MeshCoP timestamps.
 *
 */

#ifndef MESHCOP_TIMESTAMP_HPP_
#define MESHCOP_TIMESTAMP_HPP_

#include <string.h>

#include <openthread/platform/toolchain.h>

#include "common/encoding.hpp"

using ot::Encoding::BigEndian::HostSwap16;

namespace ot {
namespace MeshCoP {

/**
 * This class implements Timestamp generation and parsing.
 *
 */
OT_TOOL_PACKED_BEGIN
class Timestamp
{
public:
    /**
     * This method initializes the Timestamp
     *
     */
    void Init(void) { memset(mSeconds, 0, sizeof(mSeconds)); mTicks = 0; }

    /**
     * This method compares this timestamp to another.
     *
     * @param[in]  aCompare  A reference to the timestamp to compare.
     *
     * @retval -1  if @p aCompare is less than this timestamp.
     * @retval  0  if @p aCompare is equal to this timestamp.
     * @retval  1  if @p aCompare is greater than this timestamp.
     *
     */
    int Compare(const Timestamp &aCompare) const;

    /**
     * This method returns the Seconds value.
     *
     * @returns The Seconds value.
     *
     */
    uint64_t GetSeconds(void) const {
        uint64_t seconds = 0;

        for (size_t i = 0; i < sizeof(mSeconds); i++) {
            seconds = (seconds << 8) | mSeconds[i];
        }

        return seconds;
    }

    /**
     * This method sets the Seconds value.
     *
     * @param[in]  aSeconds  The Seconds value.
     *
     */
    void SetSeconds(uint64_t aSeconds) {
        for (size_t i = 0; i < sizeof(mSeconds); i++, aSeconds >>= 8) {
            mSeconds[sizeof(mSeconds) - 1 - i] = aSeconds & 0xff;
        }
    }

    /**
     * This method returns the Ticks value.
     *
     * @returns The Ticks value.
     *
     */
    uint16_t GetTicks(void) const { return HostSwap16(mTicks) >> kTicksOffset; }

    /**
     * This method sets the Ticks value.
     *
     * @param[in]  aTicks  The Ticks value.
     *
     */
    void SetTicks(uint16_t aTicks) {
        mTicks = HostSwap16((HostSwap16(mTicks) & ~kTicksMask) | ((aTicks << kTicksOffset) & kTicksMask));
    }

    /**
     * This method returns the Authoritative value.
     *
     * @returns The Authoritative value.
     *
     */
    bool GetAuthoritative(void) const { return (HostSwap16(mTicks) & kAuthoritativeMask) != 0; }

    /**
     * This method sets the Authoritative value.
     *
     * @param[in]  aAuthoritative  The Authoritative value.
     *
     */
    void SetAuthoritative(bool aAuthoritative) {
        mTicks = HostSwap16((HostSwap16(mTicks) & kTicksMask) | ((aAuthoritative << kAuthoritativeOffset) &
                                                                 kAuthoritativeMask));
    }

private:
    uint8_t mSeconds[6];

    enum
    {
        kTicksOffset         = 1,
        kTicksMask           = 0x7fff << kTicksOffset,
        kAuthoritativeOffset = 0,
        kAuthoritativeMask   = 1 << kAuthoritativeOffset,
    };
    uint16_t mTicks;
} OT_TOOL_PACKED_END;

}  // namespace MeshCoP
}  // namespace ot

#endif  // MESHCOP_TIMESTAMP_HPP_